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Cake day: October 16th, 2025

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  • sure, but how much memory? Here’s how I imagine it working (based on approximately zero knowledge):

    • OOM killer is triggered
    • The kernel code for the OOM killer (including heuristics) has to be swapped in. This code should only be a few KB at most so won’t actually take long.
    • The code has to be executed. To do so it needs to access information about all processes
    • Even if this information can be swapped out, it, likewise, is very small.

    So in my imagination it only takes two small blobs of data being swapped in - if kernel code and process information even can be swapped out; maybe it can be protected. Maybe you know something that ruins this picture though.



  • Isn’t this article essentially wrong because of this line:

    Ubuntu 26.10 also stops systemd-oomd being able to kill user sessions

    systemd-oomd works completely differently from the kernel OOM killer. Unless it’s changed, it just ranks everything by how much memory they’re using and picks the biggest memory hog that isn’t manually deprioritised by some config rule, and kills that. The OOM killer has a much smarter heuristic to deprioritise processes which are being actively used.

    As far as I understand, systemd-oomd was always a shoddy implementation because of this, and when it first started being used in Fedora (I don’t know about Ubuntu) also had insanely aggressive settings so that it would nobble something when you still had 20% free memory.

    The problem it was trying to solve was that Linux’s behaviour under memory pressure is actually abysmal. I have no idea if other OSes are any better, but basically once your computer starts thrashing, you’re better off rebooting it because it’ll be up again in a minute, whereas if you wait it’ll probably be half an hour if you’re lucky. The OOM killer detects actual out-of-memory, not thrashing, and so you can spend days slowly grinding your way through operations that should have taken seconds without ever triggering it. Hence systemd-oomd is designed to kick in before you actually run out of memory… and as a consequence it somewhat frequently does so too early.














  • I believe that, but… why should that be the case? It’s a convention without a reference or motivation. I remember when they were new and I really had nothing to refer to and just having no idea whether they were on or off. The fact that I’ve got used to them now isn’t really that forgivable. In contrast, checkboxes not only have convention behind them, but mimicked filling in paper forms which many people were and are familiar with anyway. The idea that “filled” is on and “empty” is off seems inherently more intuitive even if you’ve never filled in a form if you just know that the concept of forms that you fill in exists.


  • GNOME settings pages don’t have “apply” buttons. When do you think a selection from a drop-down or numerical selector takes effect?

    Yes, most settings now take effect immediately, and that’s great. (I think KDE still prefers a separate “apply” step though). That is (still) separate from the decision of how to style something which turns something on and off, which is what I’m complaining about. I don’t take any issue with having things apply immediately.

    You raise visual impairment, which is exactly why I’m complaining. Look at the image and tell me, which of the controls is on, and which is off?

    image


  • Taking effect instantly is not really indicated by the control shape; it’s indicated by whether or not the form has a button equivalent to “apply”. Settings pages with checkboxes that applied immediately have been common for years; this distinction is not nearly as clear cut as you make out. I suspect what is going on is that both toggle switches and the removal of a separate apply step has gone on gradually at the same time.

    But a good thing to think about is all the other controls: drop downs, text entry boxes, date pickers - these have no second version which might apply instantly or not! So it’s a mistake to think that information is conveyed by the look of the control.